dcopy_to_ucol.c

/*! \file
Copyright (c) 2003, The Regents of the University of California, through
Lawrence Berkeley National Laboratory (subject to receipt of any required 
approvals from U.S. Dept. of Energy) 

All rights reserved. 

The source code is distributed under BSD license, see the file License.txt
at the top-level directory.
*/

/*! @file dcopy_to_ucol.c
 * \brief Copy a computed column of U to the compressed data structure
 *
 * <pre>
 * -- SuperLU routine (version 2.0) --
 * Univ. of California Berkeley, Xerox Palo Alto Research Center,
 * and Lawrence Berkeley National Lab.
 * November 15, 1997
 * Copyright (c) 1994 by Xerox Corporation.  All rights reserved.
 *
 * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY
 * EXPRESSED OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
 *
 * Permission is hereby granted to use or copy this program for any
 * purpose, provided the above notices are retained on all copies.
 * Permission to modify the code and to distribute modified code is
 * granted, provided the above notices are retained, and a notice that
 * the code was modified is included with the above copyright notice.
 * </pre>
 */

#include "slu_ddefs.h"

int
dcopy_to_ucol(
	      int        jcol,	  /* in */
	      int        nseg,	  /* in */
	      int        *segrep,  /* in */
	      int        *repfnz,  /* in */
	      int        *perm_r,  /* in */
	      double     *dense,   /* modified - reset to zero on return */
	      GlobalLU_t *Glu      /* modified */
	      )
{
/* 
 * Gather from SPA dense[*] to global ucol[*].
 */
    int ksub, krep, ksupno;
    int i, k, kfnz, segsze;
    int fsupc, irow, jsupno;
    int_t isub, nextu, new_next, mem_error;
    int       *xsup, *supno;
    int_t     *lsub, *xlsub;
    double    *ucol;
    int_t     *usub, *xusub;
    int_t       nzumax;
    double zero = 0.0;

    xsup    = Glu->xsup;
    supno   = Glu->supno;
    lsub    = Glu->lsub;
    xlsub   = Glu->xlsub;
    ucol    = (double *) Glu->ucol;
    usub    = Glu->usub;
    xusub   = Glu->xusub;
    nzumax  = Glu->nzumax;
    
    jsupno = supno[jcol];
    nextu  = xusub[jcol];
    k = nseg - 1;
    for (ksub = 0; ksub < nseg; ksub++) {
	krep = segrep[k--];
	ksupno = supno[krep];

	if ( ksupno != jsupno ) { /* Should go into ucol[] */
	    kfnz = repfnz[krep];
	    if ( kfnz != EMPTY ) {	/* Nonzero U-segment */

	    	fsupc = xsup[ksupno];
	        isub = xlsub[fsupc] + kfnz - fsupc;
	        segsze = krep - kfnz + 1;

		new_next = nextu + segsze;
		while ( new_next > nzumax ) {
		    mem_error = dLUMemXpand(jcol, nextu, UCOL, &nzumax, Glu);
		    if (mem_error) return (mem_error);
		    ucol = (double *) Glu->ucol;
		    mem_error = dLUMemXpand(jcol, nextu, USUB, &nzumax, Glu);
		    if (mem_error) return (mem_error);
		    usub = Glu->usub;
		    lsub = Glu->lsub;
		}
		
		for (i = 0; i < segsze; i++) {
		    irow = lsub[isub];
		    usub[nextu] = perm_r[irow];
		    ucol[nextu] = dense[irow];
		    dense[irow] = zero;
		    nextu++;
		    isub++;
		} 

	    }

	}

    } /* for each segment... */

    xusub[jcol + 1] = nextu;      /* Close U[*,jcol] */
    return 0;
}